The present disclosure relates to a touch screen, a touch panel, and a method of using the same.
Typically, touch panels are used in input devices such as personal computers, laptop and tablet computers, mobile communication devices such as smart phones, and personal digital assistants (PDAs).
Recently, touch panels are used in various information processing devices because they are simple and do not malfunction frequently, and users can easily carry such information processing devices, input information and characters such as letters without use of other input devices, and easily know how to use them.
As a technology for implementing this touch panel, an array of capacitive devices is mainly used. The capacitive devices may be classified into a self-capacitance type devices and a mutual-capacitance type devices.
Firstly, self-capacitance is a technique for sensing a coordinate touched by a user by measuring a change of capacitance induced by a change in distance between a conductor and electrodes of an electrode plate that form a touch panel. Self-capacitance can sense the user's touch even when the user's touch is not directly on or over the conductor, but is in close proximity to the conductor (sometimes referred to as “proximity sensing”). However, self-capacitance sometimes has limited recognition of precise touch coordinates due to vulnerability to noise and low touch resolution.
On the contrary, mutual capacitance is a technique for recognizing the user's touch by forming an equipotential line on a conducting film that forms the touch panel, and sensing a capacitance value change in the conducting film according to the area in which the distance between the conducting film and the conductor decreases.
Mutual capacitance has a high touch resolution, but may have limited capability in proximity sensing.
Recently, as proximity sensing becomes more and more important, a method is suggested that an additional self-capacitance type pad is stacked on a mutual capacitance type touch panel. However, this method results in increases in the thickness of the touch panel and in production costs. Also, the self-capacitance type devices and the mutual capacitance devices operate separately in a single touch panel.